package pw.hais.uitl;

import java.io.IOException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import pw.hais.config.Config;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
 * DES 加密、解密
 * 
 * @author Hello_海生
 * @date 2014年7月24日
 */
public class DES {
	private static String key = Config.DES_KEY;
	
	/**
     * Description 根据键值进行加密
     * @param data 
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    public static String encrypt(String data){
        byte[] bt;
        String strs = "";
		try {
			bt = encrypt(data.getBytes(), key.getBytes());
			strs = new BASE64Encoder().encode(bt);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
        return strs;
    }
 
    /**
     * Description 根据键值进行解密
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data){
        if (data == null)return null;
        byte[] bt = null;
        try {
        	BASE64Decoder decoder = new BASE64Decoder();
	        byte[] buf = decoder.decodeBuffer(data);
	        bt = decrypt(buf,key.getBytes());
		} catch (Exception e) {
			
		}
        return new String(bt);
    }
 
    /**
     * Description 根据键值进行加密
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
 
        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
 
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey securekey = keyFactory.generateSecret(dks);
 
        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance("DES");
 
        // 用密钥初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
 
        return cipher.doFinal(data);
    }
     
     
    /**
     * Description 根据键值进行解密
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
 
        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
 
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey securekey = keyFactory.generateSecret(dks);
 
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance("DES");
 
        // 用密钥初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
 
        return cipher.doFinal(data);
    }
}
